Bifold canopy door



R. S. MEHARD Jan.` 15, 1946.

BI-FOLD cANoPY DooR 'Filed March 13, 1945 5 Sheets-Sheet 1 Il f III'Ill' Jan. l5, 1946. R. s. MEHARD FOLD CANOPY DOOR 3 Sheets-Sheet 2-Filed March 13', 1945 klan. l5, 1946. R. s. MEHARD BI -FOLD CANOPY DOORFiled March 15,l 1945 5 Sheets-Sheet 3 Patented Jan. l5, 1946 BIFOLDCANOPY DOOR Robert S. Mehard, Youngstown, Ohio, assigner to TrusconSteel Company, Youngstown, Ohio, a corporation of Michigan ApplicationMarch 13, 1945, Serial No. 582,547

1 (Cl. i60-185) Claims.

This invention relates to doors, and has particular reference toimprovements in so-called bi-fold" doors of the type comprising an upperleaf which is pivoted at or near its upper end to a building structure,at or near the topof a doorway therein, for upward and outward swingingmovement from a vertically disposed, closed position to a substantiallyhorizontally disposed, open position in which it extends, canopy-like,from the building structure at the top of the doorway, and a lower leafwhich is pivotally connected at or near its top to the upper leaf nearthe bottom thereof for inward and upward swinging movement relative to`the upper leaf from a vertically disposed, closed position to an openposition in which it underlies the upper leaf when the latter is open.

While the doors of the general type mentioned are known, their designsheretofore have been Such that they are quite heavy and requireconsiderable expensive fabrication. Accordingly, one special andimportant object of the present invention is to provide a door of thetype mentioned which, comparatively speaking, is of light weight, muchsimplified design, and which may be produced with little fabricationand, therefore, economically, in most part from standard structuralelements such as I-beams, channel members and the like.

Another special and important object of the present invention is toprovide a door of the type mentioned embodying a simpleleaf-movementcontrol-mechanism which is effective to hold the leavessecurely in both their open and their closed positions and which also iselfective to cause the lower portion of the lower leaf to move directlyvertically during initial opening and final closing movement of saidleaf, thereby to adapt said leaf for free and easy engagement with anddisengagement from simple keeper means at the bottom of the doorway andto insure that snow or the like which may become packed against thelower part of the lower leaf will not interfere with opening and closingof the door.

Another special and important object of the invention is to provide aleaf-movement-controlmechanism which is conducive to distribution ofstresses throughout the door and to free and easy operation of thelatter.

Another special and important object of the invention is to providespring means to assist in initiating opening movement of the door and tocushion opening and closing movements thereof, thus to eliminateundesirable shocks to which the door might otherwise be subjected.

With the foregoing and other objects in View, which will become morefully apparent as the nature of the invention is better understood, thesame consists in a door of the type mentioned embodying the novelfeatures of construction, combination, and arrangement 0f parts as willbe hereinafter more fully described, illustrated in the accompanyingdrawings and dened in the appended claims.

In the accompanying drawings, wherein like characters of referencedenote corresponding parts in the different views:

Figure l is a vertical section through a door constructed in accordancewith one practical embodiment of the invention and showing, in fulllines, the leaves in their vertically disposed, closed positions and, indotted lines, different positions assumed by said leaves during openingand closing of the door.

Figure 2 is an enlarged, fragmentary section, similar to Figure lshowing in detail the pivoted, slidable connection between the doorleaves.

Figure 3 is a rear elevation of the structure shown inFigure 2.

Figure 4 is an enlarged vertical section similar to Figure 2.

Figure 5 is a cross section on the line 5 5 of Figure 4; and

Figure 6 is a view similar to Figure 2 showing the leaves in partlyopened positions.

Referring to the drawings in detail, A designates a part of a buildingstructure such, for example, as an aircraft hangar, having a doorway a,and B designates, generally, a door constructed, mounted and operable inaccordance with the invention to control closing and opening of saiddoorway a.

The door B is composed of an upper leaf b and a lower leaf b', and, inaccordance with the invention, the upper leaf b is pivoted, at or nearits top, to the building structure A, at or near the top of the doorwaya therein, as indicated at I0, for swinging movements between avertically disposed, closed position, as shown by full lines in Figure1, and a substantially horizontally disposed, open position in which itextends, canopylike, from the building A, as shown by dotted lines inFigure 1. On the other hand, the lower leaf b is suitably connected, ator near its top, to the upper leaf b, near the bottom of the latter,both for limited vertical moveme'lntsl relative thereto and for swingingmovements relative thereto between a vertically disposed, closedposition and a substantially horizontally disposed open position inwhich it underlies said upper leaf b when the latter is in its openposition. In this latter connection, depending upon the width of thedoor,

there may be any desired number of vertically slidable, pivotedconnections between the leaves at any desired locations spaced apartalong the width of the door.

Further in accordance with the invention, the leaves b and b' areconnected together and to the building structure A'by arm and linkassemblies to brace the leaves and to assist in controlling theiropening and closing movements, and, as in the case of the connectionsbetween the leaves, there may be, depending upon the width of the door,any desired number of these arm and link assemblies spaced apart asdesired along the width of the door. In any event, the connectionsbetween the leaves are duplicates of one another 4and a description ofone therefore will suice for all. Likewise, the arm and link assembliesare duplicates of one another and a description of one of these willsufce for all.

While the leaves b and b' may be of any suitable constructions theyinclude vertically disposed, alined I-beams I I and I2, respectively,and in accordance with the specic embodiment of the inventionillustrated in the drawings, any given vertically slidable, pivotalconnection between said leaves includes a pair of spaced apart channelmembers I3, I3 suitably fastened rigidly at their lower ends to theupper end of an I-beam I2 of the lower leaf and rising therefrom behindthe lower portion of the related I-beam II of the upper leaf.

Extending through the upper end portions of the channel members I3, I3is a shaft I4 upon which is mounted, between said channel members, aroller I5 which engages the rear face of the related I-beam II of theupper leaf b, while mounted upon the end portions of said shaft I4 areangle members I6, I6 having anges I1 which overlie the front face of therear flange of said I-beam Il. These angle members IB thus are preventedfrom moving rearwardly relative to the I-beam I I, but are verticallyslidable with respect thereto, and since the channel members I3, I3 arepivotally connected with said angle members by the shaft I4, it followsthat the lower leaf b' is connected adjacent to its top to the lowerportion of the upper leaf for vertical sliding and pivotal movementsrelative thereto.

Fixed to the lower portion of the I-beam I I and extending rearwardlytherefrom, one to either side of the channel members I3, I3, is a pairof plates I8, I8 which carry, at their inner sides upwardly andrearwardly inclined cams I9, I9, respectively, while mounted upon thechannel members I3, I3, at the outer sides thereof, are rollers 20,20for cooperation with said cams, respectively, during initial opening andfinal closing movements of the door.

Any given arm and link assembly comprises, according to the specificembodiment of the invention illustrated in the drawings, an arm 2lpivoted at its upper end to the building structure A a suitable distanceinwardly from the doorway a at about the level of the top thereof, asindicated at 22, and a pair of links 23 and 24, each pivoted at one endto the lower end of the arm 2l, as indicated at 25, and pivotallyconnected at their opposite ends to the upper and the lower leaves b andb', respectively, as indicated at 26 and 21, respectively. As shown,each link 23 and 24 comprises two arms, but either or both of said linksmay comprise only a. single arm if desired. In any event, when the dooris closed the lower end of the arm 2| is spaced rearwardly from the doorand is disposed at about the level of the bottom of the upper leaf,while the links 23 and 24 extend upwardly and forwardly and downwardlyand forwardly, respectively, from the lower end of said arm 2| to theleaves b and b', re-

- spectively, to which they are connected at points spaced suitablyabove the bottom of the upper leaf and suitably below the top of thelower leaf| respectively. Moreover, when the door is closed, the arm 2lis inclined upwardly and rearwardly. Accordingly, each arm and linkassembly constitutes a truss `,effectively holding the upper leafagainst swinging inwardly, at its bottom and the lower leaf againstswinging inwardly at its top when the door is closed.

When the door is closed the rollers 20, 20 are disposed in front of andagainst the cams I9, I9 at the bottoms thereof, and the top of the lowerleaf b is spaced downwardly a suitable distance below the bottom of theupper leaf b, the space between said leaves then being closed by anapron 28 depending from the lower end of the upper leaf into overlappingrelationship to the top of the lower leaf. Thus, when the door isclosed, the lower leaf is capable of being raised a, limited distancerelative to the upper leaf. In this connection, suitable door operatingmeans is provided and may comprise one or more cables 29 connected tothe bottom of the lower leaf, as indicated at 30, and extending over oneor more sheaves 3l to a suitable power or manually operated drum (notshown) located wherever desired, the sheave or sheaves 3I being mountedupon th'e building structure A a suitable distance above the doorway aand preferably spaced a suitable distance inwardly therefrom. l.

The inclination and height of the cams I9 is such, in relation to thelength of the arm 2l and 40 the lengths Of the links 23 and 24, that asthe lower leaf b is lifted from its lowermost or closed position, itslower end portion is constrained to move vertically a predetermineddistance before it may shift either inwardly or outwardly. In otherwords, during initial raising of the lower leaf, the link 24 swingsupwardly and outwardly about its pivotal connection with the lower endof the arm 2| and thereby causes the top of the lower leaf to swingoutwardly, which in turn causes the lower end of the upper leaf b toswing outwardly due to the slidable, pivotal connection between theleaves. At the same time, this Outward swinging movement of the top ofthe lower leaf and the bottom of the upper leaf is controlled by theengagement of the rollers 20 with the cams I9 and by the arm 2| and thelinks 23 and 24 so that for a given amount of initial upward, openingmovement of the lower leaf b',

its lower end is constrained to move vertically without shiftinglaterally. The amount of this initial vertical movement of the bottom ofth'e lower leaf may be predetermined by a proper selection of thelengths of the arm 2| and the links 23 and 24 and by a correspondingproper inclination of the cams I9. In any event, it preferably issucient to permit the bottom of the lower leaf to rise above or clearany normal or expected height of snow or the like before the bottom ofsaid leaf partakes of any inward or outward movement. It is, moreover,sucient to permit complete disengagement of the lower leaf from anylocking means with which it may be engaged at its bottom when the dooris closed. The provision of suitable locking means for the bottom of thelower leaf thus is simplified and said locking means may simply consist,for example, of a rail 32 fastened to the floor of the building at thebottom of the doorway a and receivable in a channel member 33 carried bythe lower leaf b at the bottom thereof.

As the lower leaf b' is raised, the roller I5 rolls upwardly over therear face of the I-beam I I and the rollers roll upwardly over the frontfaces of the cams I9 until they reach the tops of said cams, whereuponfurther control of swinging movement of the leaves by said cams ceasesand devolves solely upon th'e arm 2| and the links 23 and 24. In thisconnection, it will be apparent that as raising of the lower leafprogresses, the roller 20 will ride over the tops of the cams I9 andleave the same; that the upper leaf will be swung upwardly andoutwardly; and that the lower leaf will be swung upwardly and inwardlyinto underlying relationship to said upper leaf until the leaves reachtheir fully open positions in which they extend substantiallyhorizontally, canopy-like, from the building structure A above thedoorway a.

During opening of the door the lower leaf b' will tend to continue tomove upwardly relative to the upper leaf even after the cam rollers 2Uhave been moved over and have become disengaged from th'e cams I9, andthis tendency will continue as long as the angle between the leaves isobtuse. When, however, the angle between the leaves begins to becomeacute, the tendency of the lower leaf will be to shift toward the bot-4tom of the upper leaf. In this connection, it is.

of course, desirable to limit shifting movements of the lower leafrelative to the upper leaf, and while any suitable means may be providedfor this purpose, one suitable and practical means may comprise suitableupper and lower stops 36 and 35, respectively, fastened to the I-beam IIto be engaged by the roller I5.

Although not essential, suitable spring means preferably is provided toresist downward movement of the lower leaf relative to the upper leaf,thus to avoid shocks due to the roller I5 contacting the stop 34 duringopening of the door and due to the bottom of the lower leaf engaging itskeeper means at the bottom of the doorway during final closing movementof said lower leaf. In this connection and according to the specificconstruction illustrated in the drawings, a pair of helical tensionsprings 36, 36 are connected at their lower ends to the angle membersI6, I6 respectively, and at their upper ends to the ends, respectively,of an arm 31 which is suitably suspended medially and pivotally from theupper leaf b. Accordingly, said springs tend to yieldably resist and tocushion downward movements of the lower leaf relative to the upper leafboth during opening of the door, as the leaves begin to assume an acuteangular relationship to each other and during closing of the door as thelower leaf partakes of the final portion of its downward or closingmovement. Moreover, since said springs are in tension when the door isclosed, they obviously assist in initiating upward or opening movementof the lower leaf b.

The arm 31 maybe suspended by a rod 38 from a bracket 39 by which thelink 23 is connected to the upper leaf b, and said rod may be verticallyadjustable relative to said upper leaf by a nut 40, whereby theeffective strength of the springs 36 may be varied.

When the cable or cables 2S is or are released, the door gravitates toclosed position and the leaves simply partake of the reverse of theiropening movements, the rollers 20 beginning to cooperate with the camsI9 during the final portion of closing movement of the door to insurethat the final portion of the closing movement of the bottom of thelower leaf shall be directly downwardly.

Preferably each I-beam I2 is provided at its inner side and adjacent toits bottom with a suitable bumper 6I to engage the under side of therelated arm 2l when the door is fully opened, thus to limit upwardmovement of the leaf and thereby prevent the door from becoming lockedin its fully open position.

From the foregoing description considered in connection with theaccompanying drawings, it is believed that the construction andoperation of the present door will be apparent. It is likewise believedto be clear wherein the present construction accomplishes the objectshereinbefore stated. Itis desired to point out, however, that while onlya single specific construction has been illustrated and described, theinvention is readily capable of embodiment in specifically differentconstructions within its spirit and scope as defined in the appendedclaims.

I claim:

l. A door comprising an upper leaf pivoted at its top for upward andoutward swinging movement from a vertically disposed closed position toa substantially horizontally disposed open position, a lower leaf havinga vertically slidable and pivotal connection adjacent to its top withthe lower portion of said upper leaf, means connected to the lower leaffor raising the same, means to cause the upper leaf to swing outwardlyand upwardly and the lower leaf to swing inwardly and upwardly withrespect thereto in response to raising of the lower leaf, and meanscooperating with said last-named means to cause the bottom of the lowerleaf to move directly upwardly for a predetermined distance duringinitial opening movement of the door.

2. A door comprising an upper leaf pivoted at its top for upward andoutward swinging movement from a vertically disposed closed position toa substantially horizontally disposed open position, a lower leaf havinga vertically slidable and pivotal connection adjacent to its top withthe lower portion of said upper leaf, means connected to the lower leaffor raising the same, means to cause the upper leaf to swing outwardlyand upwardly and the lower leaf to swing inwardly and upwardly withrespect thereto in response to raising of the lower leaf, and a cam anda cam follower, one on one of said leaves and the other on the other ofsaid leaves, cooperating with each other and with said last-named meansto cause the bottom of the lower leaf to move directly upwardly for apredetermined distance during initial opening movement of the door.

3. A door comprising an upper leaf pivoted at its top for upward andoutward swinging movement from a vertically disposed closed position toa substantially horizontally disposed open position, a lower leaf havinga vertically slidable and pivotal connection adjacent to its top withthe lower portion of said upper leaf, means connected to the lower leaffor raising the same, means to cause the upper leaf to swing outwardlyand upwardly and the lower leaf to swing inwardly and upwardly withrespect thereto in response to raising of the lower leaf, saidlast-named means comprising an arm having a fixed pivotal mounting atone end and a pair of links each pivotally connected at one end to theother end of said arm and respectively pivotally connected to saidleaves, and means cooperating with said arm and said links to cause thebottom of the lower leaf to move -directly upwardly for a predetermineddistance during initial opening movement of the door.

4. A door comprising an upper leaf pivotedat its top for upward andoutward swinging movement from a vertically disposed closed position toa. substantially horizontally disposed open position, a lower leafhaving a vertically slidable and pivotal connection adjacent to its topwith the lower portion of said upper leaf, means connected to the lowerleaf for raising the same, means to cause the upper leaf to swingoutwardly and upwardly and the lower leaf to swing inwardly and upwardlywith respect thereto in response to raising of the lower leaf, saidlast-named means comprising an arm having a fixed pivotal mounting atone end and a pair of links each pivotally connected at one end to theother end of said arm and respectively pivotally connected to saidleaves, and a cam and a cam follower one on one of said leaves and theother on the other of said leaves cooperating with each other and withsaid last-named means to cause the bottom of the lower leaf to movedirectly upwardly for a predetermined distance during initial openingmovement of the door. A

5. A door comprising an upper leaf pivoted at its top for swingingmovement between a vertically disposed closed position and a,substantially horizontally disposed open position, a lower leaf having avertically slidable and pivotal connection adjacent to its top with thelower portion of said upper leaf and swingable about its saidconnectio'n between a vertically disposed closed position and a.substantially horizontally disposed open position in which it underliessaid upper leaf, when the latter is open, means for raising and forcontrolling lowering of said lower leaf, means to cause the upper leafto swing outwardly and upwardly and the lower leaf to swing inwardly andupwardly relative thereto in response to raising of said lower leaf andvice versa. in response to lowering of said lower leaf, meanscooperating with said last-named means to cause the bottom of the lowerleaf to move directly vertically for a predetermined distance duringinitial opening and final closing movements of the door, and springmeans to resist and cushion downward movements of the lower leafrelative to the upper leaf.

6. A door comprising an upper leaf pivoted at itstop for swingingmovement between a vertically disposed closed position and asubstantially horizontally disposed open position, a lower leaf having avertically slidable and pivotal connection adjacent to its top with thelower portion of said upper leaf land swingable about its saidconnection Abetween a vertically disposed closed position and asubstantially horizontally disposed open position in which it underliessaid upper leaf, when the latter is open, means for raising and forcontrolling lowering of said lower leaf, means to cause the upper leafto swing outwardly and upwardly and the lower leaf to swing inwardly andupwardly relative thereto in response to raising of said lower leaf andvice versa in response to lowering of said lower leaf, means cooperatingwith said last-named means to cause the .bottom of the 1ower leaf tomove directly vertically for a predetermined distance during initialopening and nal closing movements of the door, and stop means limitingupward and downward movements of said lower leaf relative to said upperleaf.

'1. A door comprising an upper leaf pivoted at its top for swingingmovement between a, vertically disposed closed position and asubstantially horizontally disposed open position, a lower leaf having avertically slidable and pivotal connection adjacent to its top with thelower portion of said upper leaf and swingable about its said connectionbetween a vertically disposed closed position and a substantiallyhorizontally disposed open position in which it underlies said upperleaf, means for raising and for controlling lowering of said lower leaf,when the latter is open, means to cause the upper leaf to swingoutwardly and upwardly and the lower leaf to swing inwardly and upwardlyrelative thereto in response to raising of said lower leaf and viceversa in response to lowering of said lower leaf, means cooperating withsaid last-named means to cause the bottom of the lower leaf to movedirectly vertically for a predetermined distance during initi-al openingand final closing movements of the door, stop means to limit upward anddownward movements of said lower leaf relative to said upper leaf, andspring means to resist and cushion downward movements of the lower leafrelative to the upper leaf.

8. A door comprising an upper leaf pivoted at its top for swingingmovement between a vertically disposed closed position and asubstantially horizontally disposed open position, a lower leaf havinga. vertically slidable and pivotal connection adjacent to its top withthe lower portion of said upper leaf and swingable about its saidconnection between a vertically disposed closed position and asubstantially horizontally disposed open position in which it underliessaid upper leaf, when the latter is open, means for raising and forControlling lowering of said lower leaf, means to cause the upper leafto swing outwardly and upwardly and the lower leaf to swing inwardly andupwardly relative thereto in response to raising of said lower leaf andvice versa in response to lowering of said lower leaf, and meanscooperating with said last-named 4means to cause the bottom of the lowerleaf to move directly vertically for a predetermined distance duringinitial opening and nal closing movements of the door, said last-namedmeans comprising an upwardly and rearwardly inclined cam on the upperleaf below the slidable and pivotal connection between said leaves, anda. cam follower on the lower leaf in front of and engaging said cam.

9. A door comprising an upper leaf pivoted at its top for swingingmovement between a vertlcally disposed closed position and asubstantially horizontally disposed open position, a, lower leaf havinga vertically slidable and pivota1 connection adjacent to its top withthe lower portion of said upper leaf and swingable about its saidconnection between a vertically disposed closed position and asubstantially horizontally disposed open position in which it underliessaid upper leaf, when the latter is open, means for raising and forcontrolling lowering of said lower leaf, means to cause the upper leafto swing outwardly and upwardly and the lower leaf to swing inwardly andupwardly relative thereto in response to raising of said lower leaf andvice versa in response to lowering of said lower leaf, said last-namedmeans comprising an arm having a fixed pivotal mounting at its upper endbehind the door and near the level of the top thereof and a pair oflinks each pivotally connected at one end to the lower end of said armand respectively pivotally connected to said leaves above and belowtheir pivotal slidable connection with each other, an upwardly andrearwardly inclined cam on the upper leaf below the pivotal slidableconnection between said leaves, and a cam follower on the lower leaf infront of and cooperating with said cam during initial opening and nalclosing movements of said lower leaf to constrain the bottom of saidlower leaf to move directly vertically.

10. A door comprising an upper leaf pivoted at its top for swingingmovement between a vertically disposed closed position and asubstantially horizontally disposed open position, said leaf includingan I-beam extending vertically thereof and disposed at the rear thereof,a lower leaf connected near its upper end to said I-beam for verticalsliding movement relative to upper leaf and also for swinging movementrelative thereto between a vertically disposed closed position and asubstantially horizontally disposed open position in underlyingrelationship to said upper leaf when the latter is open, spring meansresisting downward movement of said lower leaf relative to said upperleaf, stop means to limit vertical sliding movement of said lower leafrelative to said upper leaf, means to raise said lower leaf, an armhaving at one end a fixed pivotal mounting at a. point spaced rearwardlyfrom the door and near the level of the top of the door, a linkconnecting the other end of said arm with the upper leaf, a second linkconnecting the said other end of said arm with the lower leaf, and camand cam follower means on said leaves, respectively, cooperating witheach other and with said arm and links to cause the bottom of the doorto move directly vertically during initial opening and final closingmovements of the door, said cam and cam follower means comprising anupwardly and rearwardly inclined cam on the upper leaf and a follower onthe lower leaf.

ROBERT S. MEHARD.

